Apparatus for coating sheet metal



H. SEBELL APPAATUS FOR GOATING SHEET METAL Filed Feb. 2s, 141

Feb. 27,- 1945.

Hurry 4 Sheets-Sheet 1 y Invenor.

SebeH byiuwkw Feb. 27, 1945. H. sEBELL APPARATUS FOR COATING SHEETv METAL Filed Feb. 26, 1941 4 Sheets-Sheet 2 Invenfor.

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y Feb. 27, 1945. H. sEBELL 2,370,495

APPARATUS FOR COATING SHEET METAL y Filed Feb. 26. 1941 4 Sheets-Sheet 3 y l InVenTor.- Hurry SebeH Feb- 27 1945; n H.' SEBI-:LL 2,370,495

APPARATUS FOR COATING SHEET METAL vl Filed Feb. 2s, 1941 4 sheets-sheet 4 Fi g4.

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Patented Feb. 27A, 1945 l UNITED STATE-s PATENToF-FICE .2,370,495A APPARATUS Fon coA'rrNG SHEET METAL lHarry Sebell, Newton, Mass., assgnor of onehalf to Arthur H. Parker, Lexington, Mass.

Application February 2.6, 1941, Serial No. 380,663

` 1 claim. (c1. si-flaz) This invention relates ltothe art of tinning sheet metal, that is, applying a coating of tin to sheet metal.

One form of apparatus now commonly used for tinning sheet metal comprises a tin pot containing molten tin through which the sheet or strip rto be `tinned is fed, said tin pot being formed on its entering side, that is, the side at which the sheet or strip enters the molten tin, with a flux box conv taining flux, and also' being formed on its discharge'lside, that is, the'side at which the sheet or strip is discharged, with a compartment containing palm oil or other suitable oil through which the tinned sheet is discharged as it emerges from the bath of molten tin. Such machines are generally provided with apair of squeeze rolls in the body of oil whichl have` for their purpose t regulate the thickness of the coating of tin with which the sheet metal is provided. These squeeze rolls have to be very accurately made and very carefully set.v If the squeeze rollers are set too far apart, then .the coating of tin which is left on the sheet l,may be unnecessarily thick.` If the surface of each squeeze roll is not vperfectlyitrue and perici-duly smooth, the result may be imperfect-ting. During the use of a. tinning apparatus of this type, impurities in particle form, such', for inother fluid may be effective in washing off impurities and surplus tin from the sheet or strip as it emerges from the bath of molten tin, it is important that such jets should impingel on the coated sheet while the tin coating is still in a uid, freelyrlowing condition and before thevcoat- *ing hardens to any. extent.

be used at a temperatureiwhich isfeither lower or higher than that of the molten an.

One advantage of this is that the thickness of the coating off'tin which remains on the strip can be controlled by varying the lternperatureof 'fthe oil. If the oil viskept 'at a temperature lower than thatof ythe moltentin, the oil jet will have a cooling effect Aon the tin,and1as a result, vless of the tin which adheres to the strip will be washed off by the` jets/than if the oil were kept stance, as iron-tin alloy particles,'scale, rust; dirt,

grit, etc., accumulate in th'eroil bath, and if any such particles are present` on the surface of the Atinned sheetswhenit passes between the squeeze rolls, such particles maybeoome embedded in the -tin sheet by the pressure of the squeeze rolls,

thereby producing a pin hole, black spot, or unparticle may adhere to the surface of the squeeze thereon.

It is one of the objects of my present invention to provide a novel substitute for the squeeze rolls by which the thickness of the tin coating that remains on the sheet may be controlled, which 'substitute is free from the disadvantages above referred to and thatare apt to result from the use of squeeze rolls. This substitute is in the form of whichare delivered'againstlthe tinned surface as it is passing through the oil bath, lsuch highfpressure jets serving not "only to wash off 'fromf the i, sheet any impuritiesin particle ronn, but also servingto wash 01T from the sheet any surplus tinthereby leaving on the sheetan even tin coatgingofvthedesired thickness."

In-order that these high pressure jefts of "oil or Il 1 desirable imperfection in the tin coating, or said` -roll, thereby producing an imperfect surface at a temperature higher than that ofthe molten tin.y Consequently, increasing the temperature of the oil issuing from the jets will vresult ina thinner coatingvof tin adhering to thev sheet, While lowering the, temperaturefof the oil will result in a thicker coating of tin adhering: to said'strip..

Other objects of the invention are to improve tin-plating apparatus in .various other yparticles as will be more fully hereinafter set forth.- In the drawings: f

Fig. 1 is avertic'al sectional view through aplating apparatus vembodying my invention. Fig. 2 isa side view thereoflooking` from side away from the observer in Fig. L- i. Fig. 3 is'v a top plan view;

, the

^ Fig. 4 is an.enlarged:verticalA section through Fig. 5 is a fragmentary' sectional view showing 'highpressure jets of oil'or other suitable fluid the-oil jets'.

the means for drivingnthe pressurefrollers,`- 1' j Fig. 6 is a fragmentary sectional-viewzshowing In the drawings,

- suitable or `usual construction; co'ntaininga-bath .2 of molten y'potl shown as' mounted in a sintablirurnace: whichfmayfbefneated by means logia E" to contain palm oil or other suitable oil 9.

The device is herein illustrated as designed for tinning' metalin the form of a strip I0 which is taken from a suitable reel that is shown as being supported in brackets I2 mounted on the furnace 3. This strip of metal extends from the reel over a direction roller I3 which is mounted on the tin pot, and from the roller I3, the strip passes downwardly through the flux bath 1 and into the bath 2 of molten tin. Situated within the bath of molten tin is a relatively large feed roll or drum |4 around which the strip passes, said strip then moving upwardlythrough the bath 9 vof oil and over a direction roller l5 whichisrotatably mounted in uprights or supports I6. From the direction roller I5, the sheet passes `downwardly under another direction roller I1 and thence horizontally over still another direction roller I8 from which it passes to a drum I9 on which it is wound.

The drum I4 is ahollow drum, and it serves two purposes. It is positively driven and, therefore constitutes a feed drum for feeding the strip through the bath of molten tin. It is also internally heated so that it constitutes a heating drum for applying heatto the stripy I0 while it is passing around through the bath of moltentin. This drum may be driven 'in any suitableway,

and as herein shown,`said drum is provided with two hollow hubs and 2l which are journaled.

in suitable bearings 80 and 8| secured to the side walls of the tin pot I. The hub 2| is a long hub4 which extends through the wall of the furnace 3 and has on its outer end a sprocket wheel- 22 that is connected by a sprocket chain 23 with a driving sprocket wheel 24. This driving sprocket 24 is mounted on a shaft 25 suitably journaledin the framework of the apparatus, and it is driven from a motor 26 through some appropriate speedreducingl apparatus that is indicated generally at 21. The motor 26, therefore, drives the shaft 25 on which the sprocket`24 is fast, and said sprocket 24 drives the drum through the sprocket.

chain 23 and sprocket wheel 22 which is fast on the hub 2| of the drum.

VProvisionfis made whereby the motor -26 may also drive the reel I9 on which the plated strip is wound. For this purpose, the shaft 25 has a sprocket wheel 28 thereon whichkis connected by a sprocket chain 29 with a sprocket wheel 30 on the shaft 3| of the reel I9.' I propose toemploy.

a slip clutch 3'2 of any usual constructionjbetween y storage tank.

the sprocket 30 and the shaft' 3| to'compensate i;

for the increasing size of the roll 33 Vof tinned strip as the-.tinning operation proceeds. The

feed roll I4 is driven at a constant rate and, thereforethe tinned strip is delivered `to thev reel I9 at a uniform rate of speed, This will necessitate a gradual decrease in the speed of rotation of saidv reel Aas the vroll 33 increases in size, and the slip clutch 32 provides for this.

In accordance with my present invention',` the tinned surfacev of the strip Iis subjected to the action of'high pressure jets of oil while it is travelling through the oil bathfand while the tin coating which has been deposited on the strip is still in a fluid free-owing condition. These high pressure oil jets serve not only to wash o any impurities which may be deposited 0n thesheet,

length equal to the width of the strip l0. These nozzles are arranged at an inclination, one on each side of the strip I0, and, as stated above, are situated in the oiI bath 9.

Means are provided for delivering sheet-like jets of oil 39 from these nozzles under pressure, each4 sheet-like jet being delivered downwardly against the strip I0.

The oil which is thus delivered from the nozzles 34, 35, is taken from a storage tank 36, and the oil compartment 8 is provided with an overflow outle't 31 to which'is connected an overflow pipe 38 that leads back'into the storagel tank 36.

, The required pressure of the jets 39 of oil as they issue from the nozzles 34, 35, is derived from the operation of a pump 40 which is shown as being operated by a suitable motor 4I. -The inlet to this pump is connected by a pipe 42 to the bottom of the storage tank 36, and the discharge of the pump is connected to a pipe 43 which is provided with a horizontal portion 44. l

Said horizontalportion 44 has two horizontal transverse pipes 45 and 46 connected thereto, which pipes extend across the oilv compartment L 8. The nozzle 34 is connected to the pipe 45, 'and valve 49 is closed; the pressure or force with which the jets 39 are delivered from the nozzles will be the maximum'pressure developed by the pump 40. If a reduction in pressure is desired, for any reason, the valve 49 can be opened more or less,

thus by-passing some of the oil back into the The operation'of the oil jets 39 serve not only to waslroi from the plated strip any impurities which may adhere thereto as it passes through the tin pot: but also. to wash 01T from the strip surplus tin, thereby leaving on the strip an even tin coating of the desired thickness. The thicknessof the coating which is'left on the strip can be varied by varying the pressure with which the jets 39 are delivered from the'nozzles 34, 35.

In order that the nozzles-may operate eiectively, however, it is important that the coating of tin which is adhering to the strip as the strip passes between the nozzles Yshould be in a sufficiently uid qr liquid state so that surplusv tin i can be readily washed on? from the strip by the.

If'the coating of tin whichaction 0f the jets.

adheres to the strip has beglm to'solidify to any extent before it is acted' on by the jets,then the jets will imperfectly perform their function Iand will not leavea coating of uniform thickness. To

A prevent this from happening and to enable the jets to function as desired, I have provided means for heating the 'feed roll I4. This heating of the feed roll serves to supply heat to the bath of moltentin interiorly of the tin pot, and because the strip Il is in direct contact `with the heatedy feed roll, the latter servesto supply heat to the strip.

is a result, when, anyv portion of the strip Il leaves the heated feed roll, such portion fof the strip will be at a high temperature; as will also be the coating of tin which adheres to the strip. Such coating of tin, therefore, retains its fluid free-flowing condition until if, reaches and is acted upon by the jets 39, which, as stated above, operate not only to wash off impurities from the strip, but also to wash off surplus tin.

Any suitable means for heating the feed drum I 4 may be employed. vI have herein shown a gas burner 5I which is located 'within the drum and is connected to a supply pipe 52 that extends through the hollow hub 2 I.

Means are also provided for heating the oil in the storage tank 36, and while any suitable means for this purpose may be used, I have illustrated a gas jet 90 located in a heating compartment SI beneath the tank and connected to a gas supply pipe 92. The means for heating the oil in the storage tank 36 which is exemplified by the burner 90, will be such that the oil in said tank may be heated to a temperature higher than that of the molten tin if desired, and by regulating the heating means, the oil in the storage tank may be kept at a temperature either the same as that of the molten tin or lower than that of the molten tin. If the oil in the tank 36 is at a lower temperature than that of the molten tin, then the oil jets 39 will have a cooling effect on the tin coating, and while such jets of oil will wash 01T impurities in particle form and will also Wash off surplus tin, yet the cooler temperature of the oil jets will result in a coating of tin of increased thickness remaining onthe strip I0.' I

On the other hand, if the oil in the storage tank is kept at a temperature higherthan that of the molten tin, these high-temperature oil jets will prevent the tin from cooling and will, therefore,

wash .off a greater quantity of the tin which is adhering to the strip, with the result that a thincontinuous circulation of4 oil from the storage tank 36 to and through the nozzles 34, 35, into the oil compartment 8, and from the latter back to the storage tank through the over-flow outlet 31 and pipe 38.

This circulatory movement ofthe oil will carry most of the impurities which are washed off from the sheet strip 19 through the overflow into the storage tank 36, thuspreventing an accumulation of such impurities in the oil bath v9.

The storage tank 36 is provided with a screen or strainer 50 which serves to strain out these impurities, -so that oil'which is withdrawn from the bottom of the storage tank and delivered to the nozzles is free from such impurities.

' Cooperating with the feed drum .I4 are two Apositively driven feed rolls '53 and 54, each roll pose, the drum has ri-gid therewith a gear 55, and leach feed roll 53, 54 has rigid therewith a pinion 56 which meshes with and is driven by the gear 55. These `feed rolls 53, 54, are mounted so that they can be adjusted toward and from the feed drum I4 to accommodate sheets or strip's of different thickness. The feed roll 53 is carried in the lower end of a rocking member 51 which is pivotally mounted at 58, and the upper end of which has connected thereto a link 59 that ex tends through en 'opening in an abutment 60. The end of the link 59 is screw-threaded and has an adjusting nut 6I thereon. By adjusting this nut 6I, the rocker 51 will be turned slightly about its axis 58, therebymoving the feed roll 53 toward or from the feed drum I4.

The feed roll 54 is similarly adjustably mounted, it being carried in the'lo'wer end of a rocker 62 pivoted at 63, and the upper end of the rocker 62 has connected thereto a link 64 which extends through an abutment 65 and has an adjusting nut 66 screw-threaded to its outer end,

61 indicate guide plates between which the strip I0 passes as it travels to the feed roll, and -68 indicate similar guide plates through which the strip passes as it leaves the feed roll I4. 69 is a curved guide plate encircling the bottom of the feed roll I4 and serving to guide the free end the temperature of the of a sheet or strip from thefeed roll 53 around to the feed roll 54 when said sheet or strip is.

ving a vpot containing` a bath of molten coating metal, said pot having an oil-containing .com-

. partment atthe delivery end thereof, means to feed a strip of sheet metal through said pot and through the oil compartment, means to deliver a sheet-like high .pressure jet of hot oil against Y to wash surplus coating metal from the sheet metal, means lto supply heat to the oil in addition to that' which it receives from the molten' coating metal, and means to supply heat to the sheet metal lin addition to that which it receives from the molten coating metal, the additional heat thus supplied to both the oil and the sheet metal serving to maintain the coating metal which adheres to the sheetmetal at a temperature at which it is in a sufciently free-flowing condition vso that the oil jet will Wash.all surplus coating metal "from the sheet metal and leave thereon. a. thin coating of uniform thickness.

HARRY SEBELL. 

